This invention relates to a wafer producing apparatus wherein a wafer is sliced out from a working piece such as a semiconductor ingot, subjected to a post-processing such as chamfering, and stored in a predetermined wafer storage portion.
A general type of wafer producing apparatus of the prior art is shown in FIG. 6. In FIG. 6, a workpiece such as a semiconductor ingot set in a slicing device 90 of the wafer producing apparatus, is sliced into pieces one after another to obtain a number of wafers therefrom. Then, the wafer sliced out of the workpiece is cleaned, has a slice base adhered thereto removed and is dried in a wafer processing device 92. The wafer thus processed by the wafer processing device 92 is transported to a chamfering device 94 where the wafer is chamfered, and then to a cleaning/drying device 96 where the wafer, after the chamfering, is cleaned and dried again. The wafer, after the cleaning and drying, is transported to a wafer storage cassette 98. There is prepared a wafer storage cassette for each workpiece. When slicing of one workpiece is finished to obtain a certain number of wafers, and these wafers are all stored in one wafer storage cassette 98, a new workpiece is set in the slicing device 90 and the wafer storage cassette 98 storing the processed wafers therein is replaced with a new empty cassette.
Generally, the number of wafers sliceable by the slicing device 90 per unit time is exceedingly small compared to the number of wafers workable by the chamfering device 94 per the same unit time as of a slicing operation by the slicing device 90. Accordingly, there is generated a long wait time (interval) for the chamfering device 94, from a chamfering operation for one wafer by the chamfering device 94 to a next chamfering operation to be conducted to a next wafer which is transported to the chamfering device 94 from the slicing device 90 and the wafer processing device 92. This would become a hindrance to an effective operation of the chamfering device 94, and greatly obstructs improvement of wafer production efficiency.